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Allosaurus
Allosaurus (al-oh-saw-us; name meaning "Other Reptile") was a large carnivorous theropod dinosaur that lived in North America during the Late Jurassic period. It was of a more primitive line of theropods than the later Tyrannosaurs for example, and this group declined with their rise. Allosaurus was one of the largest predatory dinosaurs of the Late Jurassic period, on average, measuring 9.2-10 meters long, 4-4.5 meters tall, and weighing 3-4 tons. Its maximum size was 11.6 meters long, max height of 4.9 meters tall, and a max weight of 5 tons. However, one specimen of Allosaurus (the largest ever discovered), grew to 13.8 meter long, 5 meters tall, and weighed up to 6 tons, making it one of the largest known theropods. Nevertheless, for its day, it was top of the line in a general context, and a deadly carnivore rivaled by few other theropods on Earth in the Late Jurassic period, outclassing the more primitive Coelophysis. In short, the Allosaurus were strong carnivores. They were after all, the 'Lions of the Jurassic'. Allosaurus gave its family their name, and the Allosaurs lasted for tens of millions of years, only being replaced in importance during the Cretaceous. Torvosaurus may have been a rival, one could speculate, as it was just as fearsome. Allosaurus was one of the most successful predators of its day. Facts Time/Era/Period Allosaurus was the apex predator of the Late Jurassic Period from 156–145 million years ago, ruling Western North America for 11 million years. Said to be the kings or "lion of the Jurassic", it was the largest carnivorous dinosaur of its time. It shared its environment with other creatures like Ornitholestes, Anurognathus, Brachiosaurus, Diplodocus, Apatosaurus, Stegosaurus, Dryosaurus, and Othnielia. Allosaurus was first discovered by Othniel Charles Marsh in 1877. Allosaurus was among the largest predatory dinosaurs of the Late Jurassic and was also among the largest predators until the Tyrannosaurs appeared over 50 million years later. Size/Description As the largest carnivorous dinosaur of its time and the first giant predatory dinosaur ever to walk North America, Allosaurus was a large carnivorous dinosaur, in fact one of the largest predatory dinosaurs that ever walked Planet Earth, on average, measuring 30–40 feet (9.3–12.3 m) long, standing 13–16 feet (4.2–4.9 m) tall, and weighing up to 3–5 tons (6,000–10,000 lbs). However, the largest Allosaurus ever discovered stood about 16.5 feet (5 m) tall, measured 45 feet (13.8 m) in length, and weighed up to 6.5 tons (13,000 lbs.), making it a huge carnivorous dinosaur almost as large as Tyrannosaurus rex. Even at that large, Allosaurus were such massive predators, but they were just as fast, quick, and agile as their two little ancestors: Coelophysis and Liliensternus. Allosaurus had to eat their own weight in food every month, which is equivalent to about as much as over 40 humans. From the moment they hatch from their eggs, an individual of Allosaurus could reach their full adult size in seven short years. Allosaurus had a bulky body, a massive tail and thick bones. It had a strong S-shaped neck, and had vertebrae that was different from those of other dinosaurs, hence its name. The animal had a skull that measured three feet long, with a pair of blunt crests just above its eyes, in the orbital region. Allosaurus also had large, powerful jaws with long, sharp, serrated teeth that were 2-4 inches long. Movable joints and elastic ligaments in Allosaurus jaw and skull flexed to help the teeth tear and slice through the prey. The flexible jaws stretched widely to allow the creature to swallow large mouthfuls of flesh. These teeth were curved inward, shaped like a "D" to help secure its prey. Running on two muscular, bird-like legs at speeds as fast as 20 mph, Allosaurus preyed upon the large herbivores of the period, including large sauropods, and smaller plant eaters. The forelimbs were short but muscular and had three fingered tipped hands with a sharp curved claw up to 15-25cm (6-10 inches) long for holding prey. The powerful jaws were lined with over 70 sharp 8cm (3 inch) long teeth. Behavior Like many large predators, Allosaurus was a pack hunter, possibly lying in wait to ambush prey. It could hunt in pairs, packs of three (which was their most common number), groups, or even numbers of over half a dozen individuals. But when hunting larger prey, such as Diplodocus, an Allosaurus pack would split between a Diplodocus herd, break up the herd, and isolate the weak, sick, and injured Diplodocus. For female Allosaurus, when they were mothers, smell was important to Allosaurus and from the moment the mother and hatchling Allosaurus smelled each other, they formed a bond that was crucial to the hatchlings early survival. Hatchling Allosaurus ate insects and other small animals. As young Allosaurus reached their first to second year of life, they grew to measure almost three-meters and insects would no longer be on the menu. By then, they would have already been looking for dinosaurs. Despite that, they were still small Allosaurus and they were not a match for almost all other dinosaurs on their environment, such as an overprotective female Ornitholestes. By the time a juvenile Allosaurus was five years of age, they already reached about nine meters long, yet they would be nearly, but not yet, fully grown. When Allosaurus lived to be six years old, as a sign of age, the crests over their eyes would begin to start reddening. Sexual maturity was dependent on an Allosaurus size and at 10 meters long, young Allosaurus were well on the way to be big enough. But by that time, they were more like mature adolescents instead of full sized adults. When Allosaurus reached at least 11 meters long, they could quickly establish their dominance over predatory dinosaurs, especially other Allosaurs. When predators get to the size of a fully grown Allosaurus, about 11-13 meters, most of those predators rarely had to bring down their own food. They just scavenged other kills. Journal Entry Gallery 200382518390001_03.jpg AllosaurusChicks.jpg images3.jpg|Two Allosaurus fiighting imagesCA15SKAM.jpg 200382518390001_04.jpg 200382518390001_05.jpg 200382518390001_06.jpg 1000px-Dino_trap.jpg images2.jpg Category:Prehistoric Animals Category:Jurassic Creatures Category:Dinosaurs Category:Reptiles Category:Predators Category:Jurassic Dinosaurs Category:Largest Carnivorous Dinosaurs Category:Creature of Interest Category:Most Famous Prehistoric Creatures